Tsumcorite
Tsumcorite is a rare hydrated lead arsenate mineral that was discovered in 1971, and reported by Geier, Kautz and Muller. It was named after the TSUMeb CORporation mine at Tsumeb, in Namibia, in recognition of the Corporation's support for mineralogical investigations of the orebody at its Mineral Research Laboratory.
| Tsumcorite | |
|---|---|
Tsumcorite from the Tsumeb Mine, Namibia | |
| General | |
| Category | Arsenate minerals |
| Formula (repeating unit) | PbZnFe2+(AsO4)2.H2O |
| IMA symbol | Tmc |
| Strunz classification | 8.CG.15 |
| Dana classification | 40.02.09.01 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/m (no. 12) |
| Unit cell | a = 9.124 Å, b = 6.329 Å c = 7.577 Å; β = 115.3°; Z = 2 |
| Identification | |
| Formula mass | 624.29 g/mol |
| Color | Yellow-brown, red-brown, orange |
| Crystal habit | Radiating, fibrous crusts |
| Twinning | Common, on an unknown law |
| Cleavage | Good on {001} |
| Mohs scale hardness | 4+1⁄2 |
| Luster | Vitreous |
| Streak | Yellow |
| Diaphaneity | Translucent |
| Specific gravity | 5.2 |
| Optical properties | Biaxial |
| Refractive index | nα = 1.87–1.91 nβ = 1.89–1.93 nγ = 1.92–1.96 |
| Pleochroism | Weak, yellow to yellow-green |
| 2V angle | 67–83.5° |
| Solubility | Dissolves in HCl |
| References | |
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